Garvit Agarwal

Shock wave propagation and spall failure in single crystal Mg at atomic scales

Large scale molecular dynamics (MD) simulations are carried out to investigate the wave propagation and failure behavior of single crystal Mg under shock loading conditions. The embedded atom method interatomic potential, used to model the Mg systems, is first validated by comparing the predicted Hugoniot behavior with that observed using experiments. The first simulations are carried out to investigate the effect of loading orientation on the wave propagation and failure behavior by shock loading the system along the [0001] direction (c-axis) and the [101¯0] direction using a piston velocity of 1500 m/s. The spall strength (peak tensile pressure prior to failure) is predicted to be higher for loading along the [101¯0] direction than that predicted for loading along the [0001] direction. To investigate the effect of shock pressure on the failure behavior and spall strength of the metal, the MD simulations are carried out using piston velocities of 500 m/s, 1000 m/s, 1500 m/s, and 2000 m/s for loading alon...

Atomistic study of shock Hugoniot of single crystal Mg

Molecular Dynamics (MD) simulations are carried out to investigate the shock Hugoniot for single crystal Mg using a planar shock. The MD simulations were carried out using two embedded atom method (EAM) potentials for impact velocities in the range of 500 m/s – 2000 m/s. The anisotropic behavior of shock wave propagation with loading orientation of the crystal is investigated by computing the particle velocity profiles for impact along [0001], [112¯0] and [101¯0] orientations. A split two wave (elastic-plastic) structure above the Hugoniot elastic limit is observed for all the three orientations considered. The shock pressure and the shock velocity of the elastic and the plastic wave are computed as functions of impact velocity. The Hugoniot response predicted for both the potentials agrees very well with the experimental data and therefore suggests that these can be reliably used to model the shock response of single crystal Mg.